It was shown that there was a correlation between the C diffusion coefficient and the activity coefficient of C, in austenitic Ni-Fe-Cr alloys, that could be described by:
D = D(Ni)[/Ni]0.55
where D(Ni), in m2/s, was equal to 8.7 x 10-5exp[-159.0(kJ/mol)/RT] and was close to the measured value of the C diffusion coefficient in Ni.
J.Cermák, J.Sopoušek, K.Stránský: Scripta Metallurgica et Materialia, 1993, 29[12], 1581-5
Table 184
Grain-Boundary Diffusivity of 51Cr in Ni-16.24Cr-6.78Fe-0.004wt%C
Temperature (K) | δD (m3/s) |
1346 | 6.1 x 10-20 |
1173 | 5.4 x 10-21 |
1113 | 1.4 x 10-21 |
1073 | 4.8 x 10-22 |
973 | 5.5 x 10-23 |
894 | 6.6 x 10-24 |